draft-nottingham-atompub-feed-history-09.txt   draft-nottingham-atompub-feed-history-10.txt 
Network Working Group M. Nottingham Network Working Group M. Nottingham
Intended status: Standards Track Intended status: Standards Track
Expires: October 24, 2007 Expires: November 22, 2007
Feed Paging and Archiving Feed Paging and Archiving
draft-nottingham-atompub-feed-history-09 draft-nottingham-atompub-feed-history-10
Status of This Memo Status of This Memo
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Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This specification defines three types of syndicated Web feeds that This specification defines three types of syndicated Web feeds that
enable publication of entries across one or more feed documents. enable publication of entries across one or more feed documents.
This includes "paged" feeds for piecemeal access, "archived" feeds
that allow reconstruction of the feed's contents, and feeds that are
explicitly "complete".
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Complete Feeds . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Complete Feeds . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Paged Feeds . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Paged Feeds . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Archived Feeds . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Archived Feeds . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Publishing Archived Feeds . . . . . . . . . . . . . . . . 9 4.1. Publishing Archived Feeds . . . . . . . . . . . . . . . . 9
4.2. Consuming Archived Feeds . . . . . . . . . . . . . . . . . 9 4.2. Consuming Archived Feeds . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . . 11 7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 11 7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 12
Appendix B. Use in RSS 2.0 . . . . . . . . . . . . . . . . . . . 11 Appendix B. Use in RSS 2.0 . . . . . . . . . . . . . . . . . . . 12
1. Introduction 1. Introduction
Syndicated Web feeds (using such formats as Atom [RFC4287]) are often Syndicated Web feeds (using such formats as Atom [1]) are often split
split up into multiple documents to save bandwidth, allow "sliding up into multiple documents to save bandwidth, allow "sliding window"
window" access, or for other purposes. access, or for other purposes.
This specification formalizes two types of feeds that can span one or This specification formalizes two types of feeds that can span one or
more feed documents; "paged" feeds and "archived" feeds. more feed documents; "paged" feeds and "archived" feeds.
Additionally, it defines "complete" feeds to cover the case when a Additionally, it defines "complete" feeds to cover the case when a
single feed document explicitly represents all of the feed's entries. single feed document explicitly represents all of the feed's entries.
Each has different properties and trade-offs: Each has different properties and trade-offs:
o Complete feeds contain the entire set of entries in one document, o Complete feeds contain the entire set of entries in one document,
and can be useful when it isn't desirable to "remember" and can be useful when it isn't desirable to "remember"
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this specification. this specification.
Although they refer to Atom normatively, the mechanisms described Although they refer to Atom normatively, the mechanisms described
herein can be used with similar syndication formats; see Appendix B herein can be used with similar syndication formats; see Appendix B
for one such use. for one such use.
1.1. Notational Conventions 1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119]. document are to be interpreted as described in RFC 2119 [2].
This specification uses XML Namespaces [W3C.REC-xml-names-19990114] This specification uses XML Namespaces [3] to uniquely identify XML
to uniquely identify XML element names. It uses the following element names. It uses the following namespace prefix for the
namespace prefix for the indicated namespace URI; indicated namespace URI;
"fh": "http://purl.org/syndication/history/1.0" "fh": "http://purl.org/syndication/history/1.0"
1.2. Terminology 1.2. Terminology
In this specification, "feed document" refers to an Atom Feed In this specification, "feed document" refers to an Atom Feed
Document or similar syndication instance document. It may contain Document or similar syndication instance document. It may contain
any number of entries, and may or may not be a complete any number of entries, and may or may not be a complete
representation of the logical feed. representation of the logical feed.
A "logical feed" is the complete set of entries associated with a A "logical feed" is the complete set of entries associated with a
feed (as contrasted with a feed document, which may contain a subset feed (as contrasted with a feed document, which may contain a subset
of them). of them).
"Head section" refers to a document's feed-wide metadata container; "Head section" refers to a document's feed-wide metadata container;
e.g., the child elements of the atom:feed element in an Atom Feed e.g., the child elements of the atom:feed element in an Atom Feed
Document. Document.
This specification uses terms from the XML Infoset This specification uses terms from the XML Infoset [4]. However,
[W3C.REC-xml-infoset-20040204]. However, this specification uses a this specification uses a shorthand; the phrase "Information Item" is
shorthand; the phrase "Information Item" is omitted when naming omitted when naming Element Information Items. Therefore, when this
Element Information Items. Therefore, when this specification uses specification uses the term "element," it is referring to an Element
the term "element," it is referring to an Element Information Item in Information Item in Infoset terms.
Infoset terms.
This specification also uses Atom link relations to identify This specification also uses Atom link relations to identify
different types of links; see the Atom specification [RFC4287] for different types of links; see the Atom specification [1] for
information about their syntax, and the IANA link relation registry information about their syntax, and the IANA link relation registry
for more information about specific values. for more information about specific values.
Note that URI references in link relation values may be relative, and Note that URI references in link relation values may be relative, and
when they are used they must be absolutised, as described in Section when they are used they must be absolutised, as described in Section
5.1 of [RFC3986]. 5.1 of [5].
2. Complete Feeds 2. Complete Feeds
A complete feed is a feed document that contains all of the entries A complete feed is a feed document that contains all of the entries
of a logical feed; any entry not actually in the feed document SHOULD of a logical feed; any entry not actually in the feed document SHOULD
NOT be considered to be part of that feed. NOT be considered to be part of that feed.
For example, a feed that represents a ranking that varies over time For example, a feed that represents a ranking that varies over time
(such as "Top Twenty Records" or "Most Popular Items") should not (such as "Top Twenty Records" or "Most Popular Items") should not
have newer entries displayed alongside older ones. By marking this have newer entries displayed alongside older ones. By marking this
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indicates that the feed document it occurs in is a complete indicates that the feed document it occurs in is a complete
representation of the logical feed's entries. It is an empty representation of the logical feed's entries. It is an empty
element; this specification does not define any content for it. element; this specification does not define any content for it.
Example: Atom-formatted Complete Feed Example: Atom-formatted Complete Feed
<?xml version="1.0" encoding="utf-8"?> <?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" <feed xmlns="http://www.w3.org/2005/Atom"
xmlns:fh="http://purl.org/syndication/history/1.0"> xmlns:fh="http://purl.org/syndication/history/1.0">
<title>NetMovies Queue</title> <title>NetMovies Queue</title>
<description>The DVDs you'll receive next.</description> <subtitle>The DVDs you'll receive next.</subtitle>
<link href="http://example.org/"/> <link href="http://example.org/"/>
<fh:complete/> <fh:complete/>
<link rel="self" <link rel="self"
href="http://netmovies.example.org/jdoe/queue/index.atom"/> href="http://netmovies.example.org/jdoe/queue/index.atom"/>
<updated>2003-12-13T18:30:02Z</updated> <updated>2003-12-13T18:30:02Z</updated>
<author> <author>
<name>John Doe</name> <name>John Doe</name>
</author> </author>
<id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id> <id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>
<entry> <entry>
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o "prev-archive" - A URI that refers to the immediately preceding o "prev-archive" - A URI that refers to the immediately preceding
archive document. archive document.
o "next-archive" - A URI that refers to the immediately following o "next-archive" - A URI that refers to the immediately following
archive document. archive document.
o "current" - A URI that, when dereferenced, returns a feed document o "current" - A URI that, when dereferenced, returns a feed document
containing the most recent entries in the feed. containing the most recent entries in the feed.
Subscription documents and archive documents MUST have a "prev- Subscription documents and archive documents MUST have a "prev-
archive" link relation, unless there are no preceding archives archive" link relation, unless there are no preceding archives
available. Additionally, archive documents SHOULD have "next- available. Archive documents SHOULD also have a "next-archive" link
archive" and "current" link relations. relation, unless there are no following archives available.
Archive document SHOULD also contain an fh:archive element in their Archive documents SHOULD indicate their associated subscription
documents using the "current" link relation.
Archive documents SHOULD also contain an fh:archive element in their
head sections to indicate that they are archives. fh:archive is an head sections to indicate that they are archives. fh:archive is an
empty element; this specification does not define any content for it. empty element; this specification does not define any content for it.
Example: Atom-formatted Subscription Document Example: Atom-formatted Subscription Document
<?xml version="1.0" encoding="utf-8"?> <?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom"> <feed xmlns="http://www.w3.org/2005/Atom">
<title>Example Feed</title> <title>Example Feed</title>
<link href="http://example.org/"/> <link href="http://example.org/"/>
<link rel="self" href="http://example.org/index.atom"/> <link rel="self" href="http://example.org/index.atom"/>
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</author> </author>
<id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id> <id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>
<entry> <entry>
<title>Atom-Powered Robots Scheduled To Run Amok</title> <title>Atom-Powered Robots Scheduled To Run Amok</title>
<link href="http://example.org/2003/11/24/robots_coming"/> <link href="http://example.org/2003/11/24/robots_coming"/>
<id>urn:uuid:cdef5c6d5-gff8-4ebb-assa-80dwe44efkjo</id> <id>urn:uuid:cdef5c6d5-gff8-4ebb-assa-80dwe44efkjo</id>
<updated>2003-11-24T12:00:00Z</updated> <updated>2003-11-24T12:00:00Z</updated>
<summary>Some text from an old, different entry.</summary> <summary>Some text from an old, different entry.</summary>
</entry> </entry>
</feed> </feed>
In this example, the feed archives are split into monthly chunks, and
the subscription document points to the most recent complete archive
"http://example.org/2003/11/index.atom" using the "prev-archive"
relation. That document, in turn points to the previous archive
"http://example.org/2003/10/index.atom", and so on. Note that the
"2003/11" archive does not have a "next-archive" relation, because it
is the most recent complete archive; although another archive
("2003/12") may be under construction, it would be an error to link
to it before completion.
4.1. Publishing Archived Feeds 4.1. Publishing Archived Feeds
The requirement that archive documents be stable allows clients to The requirement that archive documents be stable allows clients to
safely assume that if they have retrieved one in the past, it will safely assume that if they have retrieved one in the past, it will
not meaningfully change in the future. As a result, if an archive not meaningfully change in the future. As a result, if an archive
document's contents are changed, some clients may not become aware of document's contents are changed, some clients may not become aware of
it. it.
Therefore, if a publisher requires a change to be visible to all Therefore, if a publisher requires a change to be visible to all
users (e.g., correcting factual errors), they should consider users (e.g., correcting factual errors), they should consider
publishing the revised entry in the subscription feed, in addition to publishing the revised entry in the subscription document, in
(or instead of) the appropriate archive feed. Conversely, addition to (or instead of) the appropriate archive document.
unimportant changes (e.g., spelling corrections) might be only Conversely, unimportant changes (e.g., spelling corrections) might be
effected in archive feeds. only effected in archive documents.
Publishers SHOULD construct their feed documents in such a way as to Publishers SHOULD construct their feed documents in such a way as to
make duplicate removal unambiguous (see Section 4.2). make duplicate removal unambiguous (see Section 4.2).
Publishers are not required to make all archive documents available; Publishers are not required to make all archive documents available;
they may refuse to serve (e.g., with HTTP status code 403 or 410), or they may refuse to serve (e.g., with HTTP status code 403 or 410), or
be unable to serve (e.g., with HTTP status code 404) an archive be unable to serve (e.g., with HTTP status code 404) an archive
document. document.
4.2. Consuming Archived Feeds 4.2. Consuming Archived Feeds
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of a feed document is determined by its feed-level atom:updated of a feed document is determined by its feed-level atom:updated
element. element.
Clients SHOULD warn users when they are not able to reconstruct the Clients SHOULD warn users when they are not able to reconstruct the
entire logical feed (e.g., by alerting the user that an archive entire logical feed (e.g., by alerting the user that an archive
document is unavailable, or displaying pseudo-entries that inform the document is unavailable, or displaying pseudo-entries that inform the
user that some entries may be missing). user that some entries may be missing).
5. IANA Considerations 5. IANA Considerations
The "previous", "next" and "current" link relations have been
previously registered, and no IANA action regarding them is required.
This specification defines the following new relations, to be added This specification defines the following new relations, to be added
to the Link Relations registry: to the Link Relations registry:
o Attribute Value: prev-archive o Attribute Value: prev-archive
o Description: A URI that refers to the immediately o Description: A URI that refers to the immediately
preceding archive document. preceding archive document.
o Expected display characteristics: none o Expected display characteristics: none
o Security considerations: See [ this document ] o Security considerations: See [ this document ]
o Attribute Value: next-archive o Attribute Value: next-archive
o Description: A URI that refers to the immediately o Description: A URI that refers to the immediately
following archive document. following archive document.
o Expected display characteristics: none o Expected display characteristics: none
o Security considerations: See [ this document ] o Security considerations: See [ this document ]
Additionally, the "previous," "next" and "current" link relations
should be updated to refer to this document.
6. Security Considerations 6. Security Considerations
Feeds using this mechanism have the same authentication and channel Feeds using this mechanism have the same security considerations as
security concerns as explained in Atom [RFC4287]. Atom [1]. Encryption and authentication security services can be
obtained by encrypting and/or signing the feed, as described in [1],
and may also be obtained through channel-based mechanisms (e.g., TLS
[6], HTTP authentication [7]) and/or transport (e.g., IPSec [8]).
Feeds using these mechanisms could be crafted in such a way as to Feeds using these mechanisms could be crafted in such a way as to
cause a client to initiate excessive (or even an unending sequence cause a client to initiate excessive (or even an unending sequence
of) network requests, causing denial of service (either to the of) network requests, causing denial of service (either to the
client, the target server, and/or intervening networks). Clients can client, the target server, and/or intervening networks). Clients can
mitigate this risk by requiring user intervention after a certain mitigate this risk by requiring user intervention after a certain
number of requests, or by limiting requests either according to a number of requests, or by limiting requests either according to a
hard limit, or with heuristics. Servers can mitigate this risk by hard limit, or with heuristics. Servers can mitigate this risk by
denying requests that they consider abusive (e.g., by closing the denying requests that they consider abusive (e.g., by closing the
connection, or generating an error). connection, or generating an error).
Clients should be mindful of resource limits when storing feed Clients should be mindful of resource limits when storing feed
documents. To reiterate, they are not required to always store or documents. To reiterate, they are not required to always store or
reconstruct the feed when conforming to this specification; they only reconstruct the feed when conforming to this specification; they only
need inform the user when the reconstructed feed is not complete. need inform the user when the reconstructed feed is not complete.
This specification does not define what it means when a logical
feed's component feed documents have different security mechanisms
applied.
7. References 7. References
7.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in [1] Nottingham, M. and R. Sayre, "The Atom Syndication Format",
RFCs to Indicate Requirement Levels", RFC 4287, December 2005.
BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Masinter, "Uniform Resource Levels", BCP 14, RFC 2119, March 1997.
Identifier (URI): Generic Syntax",
STD 66, RFC 3986, January 2005.
[RFC4287] Nottingham, M. and R. Sayre, "The [3] Bray, T., Hollander, D., and A. Layman, "Namespaces in XML", W3C
Atom Syndication Format", RFC 4287, REC REC-xml-names-19990114, January 1999.
December 2005.
[W3C.REC-xml-infoset-20040204] Cowan, J. and R. Tobin, "XML [4] Cowan, J. and R. Tobin, "XML Information Set (Second Edition)",
Information Set (Second Edition)", W3C REC REC-xml-infoset-20040204, February 2004.
W3C REC REC-xml-infoset-20040204,
February 2004.
[W3C.REC-xml-names-19990114] Bray, T., Hollander, D., and A. [5] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Layman, "Namespaces in XML", W3C Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
REC REC-xml-names-19990114, January 2005.
January 1999.
7.2. Informative References 7.2. Informative References
[RSS2] Winer, D., "RSS 2.0 Specification", [6] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS)
2005, <http://blogs.law.harvard.edu/ Protocol Version 1.1", RFC 4346, April 2006.
tech/rss>.
[7] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP Authentication:
Basic and Digest Access Authentication", RFC 2617, June 1999.
[8] Kent, S. and K. Seo, "Security Architecture for the Internet
Protocol", RFC 4301, December 2005.
[9] Winer, D., "RSS 2.0 Specification", 2005.
Appendix A. Acknowledgements Appendix A. Acknowledgements
The author would like to thank the following people for their The author would like to thank the following people for their
contributions, comments and help: Danny Ayers, Thomas Broyer, Lisa contributions, comments and help: Danny Ayers, Thomas Broyer, Lisa
Dusseault, Stefan Eissing, David Hall, Bill de Hora, Vidya Narayanan, Dusseault, Stefan Eissing, David Hall, Bill de Hora, Vidya Narayanan,
Aristotle Pagaltzis, John Panzer, Dave Pawson, Garrett Rooney, Robert Aristotle Pagaltzis, John Panzer, Dave Pawson, Garrett Rooney, Robert
Sayre, James Snell, Henry Story. Sayre, James Snell, Henry Story, Franklin Tse.
Any errors herein remain the author's, not theirs. Any errors herein remain the author's, not theirs.
Appendix B. Use in RSS 2.0 Appendix B. Use in RSS 2.0
As previously noted, while this specification's extensions are As previously noted, while this specification's extensions are
described in terms of the Atom feed format, they are also useful in described in terms of the Atom feed format, they are also useful in
similar formats. This informative appendix demonstrates how they can similar formats. This informative appendix demonstrates how they can
be used in an RSS 2.0-formatted [RSS2] feed. be used in an RSS 2.0-formatted [9] feed.
In RSS 2.0-formatted feeds, two entries are duplicates if they have In RSS 2.0-formatted feeds, two entries are duplicates if they have
the same guid element. The update time of an entry is not defined by the same guid element. The update time of an entry is not defined by
RSS 2.0, but the feed-level update time can be determined by the RSS 2.0, but the feed-level update time can be determined by the
pubDate element. pubDate element.
RSS 2.0-formatted Complete Feed RSS 2.0-formatted Complete Feed
<?xml version="1.0"?> <?xml version="1.0"?>
<rss version="2.0" <rss version="2.0"
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<managingEditor>editor@example.com</managingEditor> <managingEditor>editor@example.com</managingEditor>
<webMaster>webmaster@example.com</webMaster> <webMaster>webmaster@example.com</webMaster>
<atom:link rel="next" <atom:link rel="next"
href="http://liftof.nasa.gov/index.rss?page=2"/> href="http://liftof.nasa.gov/index.rss?page=2"/>
<item> <item>
<title>Star City</title> <title>Star City</title>
<link>http://liftoff.nasa.gov/2003/06/news-starcity</link> <link>http://liftoff.nasa.gov/2003/06/news-starcity</link>
<description>How do Americans get ready to work with Russians <description>How do Americans get ready to work with Russians
aboard the International Space Station? They take a crash course aboard the International Space Station? They take a crash course
in culture, language and protocol at Russia's <a in culture, language and protocol at Russia's <a
href="http://howe.iki.rssi.ru/GCTC/gctc_e.htm"&amp;gt;Star href="http://howe.iki.rssi.ru/GCTC/gctc_e.htm">Star
City</a>.</description> City</a>.</description>
<pubDate>Tue, 03 Jun 2003 09:39:21 GMT</pubDate> <pubDate>Tue, 03 Jun 2003 09:39:21 GMT</pubDate>
<guid>http://liftoff.nasa.gov/2003/06/03.html#item573</guid> <guid>http://liftoff.nasa.gov/2003/06/03.html#item573</guid>
</item> </item>
</channel> </channel>
</rss> </rss>
RSS 2.0-formatted Subscription Document RSS 2.0-formatted Subscription Document
<?xml version="1.0"?> <?xml version="1.0"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"> <rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
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<webMaster>webmaster@example.com</webMaster> <webMaster>webmaster@example.com</webMaster>
<atom:link rel="prev-archive" <atom:link rel="prev-archive"
href="http://liftoff.nasa.gov/2003/05/index.rss"/> href="http://liftoff.nasa.gov/2003/05/index.rss"/>
<item> <item>
<title>Star City</title> <title>Star City</title>
<link>http://liftoff.nasa.gov/2003/06/news-starcity</link> <link>http://liftoff.nasa.gov/2003/06/news-starcity</link>
<description>How do Americans get ready to work with Russians <description>How do Americans get ready to work with Russians
aboard the International Space Station? They take a crash course aboard the International Space Station? They take a crash course
in culture, language and protocol at Russia's <a in culture, language and protocol at Russia's <a
href="http://howe.iki.rssi.ru/GCTC/gctc_e.htm"&amp;gt;Star href="http://howe.iki.rssi.ru/GCTC/gctc_e.htm">Star
City</a&amp;gt;.</description> City</a>.</description>
<pubDate>Tue, 03 Jun 2003 09:39:21 GMT</pubDate> <pubDate>Tue, 03 Jun 2003 09:39:21 GMT</pubDate>
<guid>http://liftoff.nasa.gov/2003/06/03.html#item573</guid> <guid>http://liftoff.nasa.gov/2003/06/03.html#item573</guid>
</item> </item>
</channel> </channel>
</rss> </rss>
RSS 2.0-formatted Archive Document RSS 2.0-formatted Archive Document
<?xml version="1.0"?> <?xml version="1.0"?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" <rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:fh="http://purl.org/syndication/history/1.0"> xmlns:fh="http://purl.org/syndication/history/1.0">
 End of changes. 30 change blocks. 
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